The present invention generally relates to apparatus and methods by which contact lenses can be protectively encased. More particularly, the invention relates to apparatus including substance and of a construction by which a lens can be safely encased for the protection of the lens and by which the application of treatment procedures to the lens is facilitated. Advantageously, the present invention is useful in protecting the lens from possible damage during period when the lens is separated from the cornea and is being treated.
A contact lens is a small, shell-shaped device having a dominant concave surface and a dominant convex surface meeting at a dominant, curved surrounding edge. Contact lenses can be made of a variety of materials. Glass is one type of such material. However, in order to provide a lens that does not easily crack, that is light, in weight and that can conform to the varying contours of the cornea, lenses are now being made from materials other than glass. Plastic materials, such as hydrogel plastics, are one group of such materials from which lenses are now widely made. Hydrogel plastics have the unique property of being able to absorb and bind a proportionality large amount of water within a polymer network. A very flexible, pliant, and soft-feeling structure results. Lenses made from hydrated hydrogel plastics are comfortable to wear because they easily conform to the cornea of the eye.
However, one serious drawback associated with lenses, regardless of the material from which they are made, is that they are easily contaminated. The simple handling of the lens by the user, such as during the placement of or the adjustment of the lens on the eye, can deposit a variety of foreign organic and inorganic materials on the lens. Once in place on the eye, a lens readily collects the oily and sebaceous substances and protein secreted by the eye. A lens positioned on the eye can collect also airborne chemicals and biological agents such as bacteria, viruses, and fungus.
Contaminants generally remain at the surface of the lenses made from the harder, non-porous materials, such as glass. However, lenses made from hydrogel plastic materials, when hydrated, form a porous polymer subsurface network into which water-soluble substances and ions can readily enter and become lodged. With time, and especially after one or more attempts to clean the lens through known cleaning techniques, the surface of the hydrogel lens tends to develop pin holes, cracks, and/or microscopic defects. Into and through these openings, proteins and pathogens, such as viruses and bacteria, can move. Through this mechanism, contaminants can collect not only at, but also below the surface of the lenses made from the new softer materials.
The contamination of lenses is a variable, but generally rapid occurring phenomenon. It has been found that fifty percent of a lens surface may be covered by deposits after a lens has been worn for only thirty minutes. After 8 hours, ninety percent of the lens surface may be coated. Complete coverage occurs typically within a matter of weeks.
Contaminants can degrade the optical performance of a lens. Sufficient layers of contaminants can accumulate on and within the lens to form a colored and/or partially opaque layer of oil, mucous, and crystalline deposits. The amount of light transmitted through the lens--and, therefore, visual acuity--diminishes depending on the composition, thickness, and extent of the contamination coating.
Contaminants can degrade also the mechanical performance of a lens by roughening the surface of a lens. The once smooth, easy-to-wear device, across whose convex surface the wearer's eyelid can glide, is transformed with time into a roughened source of irritation. Abrasions and giant papillary conjunctivitis may follow.
The cornea of the eye remains healthy and transparent only if it is kept wet and oxygenated. The tear film normally keeps the corneal epithelium wet and supplies it with oxygen from the atmosphere. The tears that can flow under and around a clean lens normally keep the cornea wet and oxygenated. However, contamination of a lens can ultimately decrease the amount of tears, and thereby the oxygen delivered to a lens. When the cornea is deprived of oxygen, anaerobic glycolysis is caused. The cornea can swell and become hazy.
A coating of contaminants on a lens can physiologically affect the eye in other ways. Contaminants can serve as an environment in which microorganisms, such as bacteria, fungi, and yeast, can flourish. Conditions such as conjunctivitis may result.
A variety of agents and techniques have been devised in an effort to remove contaminants from a lens. Known agents--such as surfactants, oxidants, disinfectants, enzymatic cleaners, and abrasives--and techniques, such as those utilizing the described agents and others, are typically directed to the removal of only one or a few types of contaminants that may collect on the surface of a lens.
Other conventional agents, methods, and devices are not necessarily directed to the removal of contaminants from the lens but to the deactivation of the pathogenic component of the contamination layer. One example of such a bacterial deactivation device is taught in U.S. Pat. No. 4,202,740.
In an attempt to improve the effectiveness of some of these known agents and techniques, mechanical devices are often used in combination with them. Such mechanical devices vibrate, rotate, scrub, heat, agitate and/or direct ultrasonic waves to a lens in an attempt to further dislodge and/or deactivate those elements fouling a lens.
Conventional cleaning agents and methods, even with the assistance of conventional mechanical devices, are limited in their effectiveness. Some of these agents, methods, and devices may be able to remove a portion of the contaminants from the surface of a lens, yet are largely unable to remove the large percentage of contaminants from and below the surface of lenses made from the newer, softer materials.
In addition to having limited effectiveness in the removal of contaminants, some techniques and devices can actually exacerbate the contamination problem by denaturing the protein component of the contamination coating. An intractable layer of contamination forms. With time, and as new layers of contaminants accrete on the older layers of contaminants, the contamination layer extends and thickens. Because of the increased irritation and the decreased visual acuity caused by this layer, lenses must eventually be replaced with new lenses. Typically, the replacement of lenses is required within one year.
Other conventional lens cleaning and/or contamination removal agents, methods, and devices may cause damage to lenses particularly those made from the newer, softer materials. For example, abrasive powders, pads, and solutions are known to remove some of the contamination from the surface of the lens. However, the use of such abrasives can scratch or otherwise damage the surface of the lens.
Other agents, methods, and devices may produce byproducts that can cause damage to a lens. For example, certain conventional devices and techniques immerse contact lenses in a fluid bath through which an electric current is established. However, these devices are constructed and/or may be used such that the electric current is of a sufficiently high voltage that dissociation of the elements of the fluid bath is caused. Depending on the composition of the fluid bath, chemical species such as Cl.sup.- or HClO may be produced. While these chemical species may kill, for example, bacteria on the lens immersed in the electrified bath, they also may also damage the material from which the lens is made.
In response to the demand for apparatus and methods by which a wide range of contaminants can be removed efficiently and safely from contact lenses, the inventor of that which is described in the present application has invented a novel lens decontamination system. The system removes contaminants from and below the surface of a lens electrokinetically by the complete application of opposing electrical charges to the lens and without the need for the total immersion of the lens in a fluid bath. The lens decontamination system is the subject of an application for Letters Patent filed concurrently with and incorporated completely by reference in this application.
The present invention is directed to the protection of a lens during the period it is separated from the eye and by which the treatment of lens can be facilitated, such as through the use of the lens decontamination system taught in the copending patent application.
The present invention is a packet. The packet is of a structure and includes a substance or substances by which a lens can be protectively encased and which facilitates the treatment of the lens. Such treatment includes the cleaning of the lens, such as that directed to the deactivation of pathogens and organisms on the lens and that directed to the removal of contaminants from the lens. One embodiment of the present invention, for example, facilitates the complete application of electrical charges to the entire surface, including the edge area of a lens, such as with the system taught in the copending patent application. Such treatment includes also surrounding a lens in a moist environment to maintain a lens at its optimum moisture level.
The substance or substances may be sufficiently pliant so that the entire surface of the lens, including the surrounding edge area, can be covered thereby. The entire surface of a lens stored within the packet, accordingly, can be treated.
The packet substance or substances may be composed of material that can accept and retain moisture. The packet substance or substances may also have an appreciable moisture content. Advantageously, a hydrated lens encased within such moist substance or substances does not dry out after separation from the cornea.
Compared to the more complex, multi-component conventional lens storage containers, the packet of the present invention is of a simple construction. One embodiment of the packet includes separate sections that open to provide opposing faces between which a lens can be completely encased and without the damaging bending, compression, and/or contortion of the lens.
The packet preferably ensures that pathogens and/or contaminants on or within a lens that is being treated cannot readily migrate to the outside of the packet. Such a packet provides a closed encasement system that allows a lens to be treated without the danger of contamination or infection of other individuals or surfaces.
While the packet may be made from material that can be reused, the packet may be made also from materials that are generally intended for a single treatment procedure and disposal. Any health risks associated with the treatment of a contaminated contact lens are thereby lessened.
The packet preferably includes also simplified opening and closing means, thereby facilitating the use of the packet by even those with temporarily limited vision.
As a means for storing a lens, the present invention has a variety of advantages over conventional devices. Conventional storage devices, such as those in which lenses are stored during a cleaning procedure, generally consist of containers having multiple pieces, including doors, covers, or lids that must be fitted, snapped, or screwed together, or closed in order to form a storage space. It is not uncommon for an individual--particularly one who has removed his or her lenses and, accordingly, has limited vision--to knick or catch a portion of the lens during the fitting, snapping, screwing, or closing of the doors, covers, or lids of the container. Furthermore, the storage space provided by known containers is such that a lens is generally only loosely held during a treatment procedure. Accordingly, the likelihood that a lens will be contorted, bent, overly compressed, or otherwise damaged while held within one of these devices and subjected to known treatment techniques, such as spinning, vibrating, or heating, and/or ultrasonic treatment, is increased.
Certain preferred embodiments of the present invention are structured and including substance or substances such that a lens can be treated according to the lens decontamination system taught in the copending application. This system includes a cleaning assembly. The packets embodiments useable in this system include a substance or substances and a structure by which opposing electrical charges can be transferred to the entire surface, including the surrounding edge of the lens. In order to treat a lens according to this system, the user places his or her lens in the protective encasement packet. The packet is placed in the cleaning assembly such that the outer faces of the packet contact electrically chargeable surfaces exposed from the assembly. In such a position, opposing electrical charges are transferred from the charged assembly surfaces through the packet substance or substances and to the lens. Contaminants are drawn from the lens and into the substance or substances. After the application of electrical charges, the packet is removed. The lens is removed from the packet. After, for example, rinsing and soaking in saline solution, the lens may be placed back onto the eye. Accordingly, the lens, including lens edge area, as completely encased during the treatment procedure, is entirely cleaned and in less time than conventional methods. The partial cleaning or shadow effects of conventional apparatus and methods that enclose or partially enclose a lens within a container is avoided. The preferred embodiments of the present invention also eliminate the need for the coordinated and time-consuming use of, for example, a container for holding fluids, fluids, and tablets that some conventional treatment procedures require. To prevent contamination and/or infection of other surfaces or individuals and in order to facilitate clean-up, the packet may be made of inexpensive materials allowing the packet to be discarded.
It is, accordingly, a general object of the present invention to provide apparatus and methods by which a lens can be completely protected during the period it is separated from the cornea.
Another object of the present invention is to provide apparatus by which a lens, including its dominant curved surfaces and surrounding edge, can be completely encased and without damage to the lens.
Also an object of the present invention is to provide apparatus including a substance or substances by which a lens can be protectively encased and that facilitates the treatment of the lens.
A further object of the present invention is to provide apparatus including a substance or substances in which a lens can be protectively encased and by which treatment may be applied to opposing sides and the edges of a lens.
An added object of the present invention is to provide apparatus including a substance or substances in which a lens can be protectively encased and that facilitates the uniform treatment of a lens by the complete application of electrical charges to the entire surface of a lens.
An additional object of the present invention is to provide apparatus including a substance or substances through which electrical charges may be transferred uniformly to the entire surface of a lens and into which contaminants are removed from the lens.
Another object of the present invention is to provide a closed system for the protective encasement and treatment of a lens.
An added object of the present invention is to provide apparatus including a substance or substances into which contaminants removed from a lens are trapped to prevent contamination and infection of other surfaces or individuals.
These and other objects, features, and advantages of the invention will be clearly understood and explained with reference to the accompanying drawings and through a consideration of the following detailed description of the preferred embodiments.